The present invention relates generally to high pressure pumps, and more particularly to the fluid end of such pumps.
High-pressure reciprocating fluid pumps have been used for many years in various industries to pressurize incompressible fluids to pressures upwards of 10 kpsi. A primary use of such pumps is for pumping drilling fluid downhole, such as mud, during oil well drilling. Such pumps are also used to provide pressurized fluid for fracking operations, water-blasting, slurry transport for oil fields, coal slurry transport from a mine to a power station, and other applications where liquids with high solid content must be transported from one location to another.
Because of the cyclic pressures (atmospheric to 10 kpsi or more) of these high pressure reciprocating fluid pumps, and the use of abrasive process fluids, the operating environment of such pumps is very demanding. Because of the high cyclical pressures encountered in the fluid end portions of these pumps, their components, such as the suction module and valves are susceptible to fatigue failure and wear.
Moreover, the suction modules of the fluid end portions of many high-pressure reciprocating pumps require cross-bores, which intersect the pump cylinder, to deliver and carry away the process fluid. These intersecting cross-bores create stress concentrations, and thus further contribute to fatigue failure of the suction modules of the fluid end portions of such pumps. Thus, many known fluid end portions require high-strength materials in an attempt to avoid fatigue failure. U.S. Pat. No. 3,260,217 to Thresher, for example, discloses a typical fluid end portion having intersecting cross-bores.
Moreover, because of high pump pressures, leakage from such pumps becomes a problem when the valves begin to wear. Some known pumps use the pressure of the process fluid to hydrostatically bias the valve assembly in engagement with the connector block or cylinder. These pumps require heavy discharge manifolds to contain the high pressure encountered and are still susceptible to fatigue failure and wear. The weight and bulk of these discharge manifolds requires more than one person to remove the manifold for repair of the fluid end portion of the pump. Such configurations are therefore labor-intensive, time-consuming, and result in expensive downtime of the fluid pump. Since the repairs must be made at the site of the fluid pump, and thus at the sight of down-hole operations and so on, exposure to adverse weather conditions further contributes to the difficulties associated with removal and replacement of the worn or broken parts.
It would therefore be desirable to provide a fluid end portion that reduces the operating stresses of the suction module of the fluid end portion of high-pressure reciprocating pumps to thereby overcome one or more of the afore-mentioned disadvantages of the prior art.